Versus Tablets (sold mostly in the UK and Ireland until 2014) have some great features (like HDMI out and Bluetooth), but power is a problem. They do not charge through the USB port, but through a 3.5mm barrel jack plug (specs are 5v 2000mA).
The power cable on my Versus Android Tablet keeps popping out (and therefore the tablet won't charge). Lately it got so bad that the plug simply wouldn't go in at all. I did a bit of research and came up with a fix.
There's a small plastic ring at the top of the plug. Take a precision pliers and pull the ring off the plug. BE CAREFUL! - If you damage the plug it simply won't go in at all, and your tablet will be useless.
Without this ring the plug stays in and the tablet charges. It still pops out occasionally, but a lot less than it did before.
NB: I do see some replacement power adapters with these plugs available on eBay and Amazon, so you may be able to try out a replacement power supply too.